This invention relates to the production of 5-aminotetrazole. More particularly, the invention relates to improvements in making this valuable chemical, including a one-pot process for the commercial manufacture of 5-aminotetrazole economically and in improved quality and yield.
The compound 5-aminotetrazole, hereinafter alternatively referred to by the abbreviated name "5-ATZ" is a well-known chemical intermediate which is also used in making propellants. In recent years, it has been found of utility in an increasing number of non-military applications including for example the production of automotive air bags.
However, only limited information has been published in the technical literature on methods of synthesizing 5-ATZ. Briefly, according to the prior art dating back to 1901, 5-ATZ can be synthesized by one of two routes which are described in two old German publications. The first involves the diazotization of aminoguanidinium nitrate with sodium nitrite and nitric acid to form a guanylazide salt intermediate which is then cyclized by heating in the presence of sodium acetate to 5-aminotetrazole. See Thiele, Ann. 270, 54 (1892).
The second method, according to the prior art, for producing 5-ATZ reacts hydrazoic acid, derived from sodium azide and an acid, with cyanamide or dicyandiamide. See Hantsch and Vogt, Ann. 314, 339 (1901).
These prior art methods are not well suited for the efficient, economically feasible production of 5-ATZ on an commercial scale. Moreover, the product of the first method typically is plagued with objectionable yellowish discoloration, the removal of which would add substantially to the cost of manufacture of 5-aminotetrazole.